Fresh Insights Into Variable Mortality From Subarachnoid Hemorrhage Across Regions of Finland

Abstract

Subarachnoid hemorrhage (SAH), mainly from ruptured cerebral aneurysm, has a relatively low frequency (5%–9.7%),1,2 but its 30-day case fatality is the highest amongst stroke subtypes (41%–46%, for combined in-hospital deaths and out-of-hospital sudden deaths3). Although the overall crude incidence worldwide is approximately 8 per 100,000 person-years,1 such rates range from 5 to 28 across countries, although much of this variability is due to differences in the methods of case ascertainment and in defining study populations across reports. In Finland, however, a consistently high incidence of SAH has long been recognized, which has led to ongoing and extensive epidemiologic and clinical investigation. Substantial geographic variability in the incidence of SAH has also been noted across the country, with associations in relation to age, sex, and risk factors.4 In this issue of Neurology®, Asikainen et al.5 publish a study in which they extend their prior observations into an analysis of regional differences in deaths from SAH in Finland.